HIV-1 Matrix Dependent Membrane Targeting Is Regulated by Gag mRNA Trafficking

Retroviral Gag polyproteins are necessary and sufficient for virus budding. Productive HIV-1 Gag assembly takes place at the plasma membrane. However, little is known about the mechanisms by which thousands of Gag molecules are targeted to the plasma membrane. Using a bimolecular fluorescence complementation (BiFC) assay, we recently reported that the cellular sites and efficiency of HIV-1 Gag assembly depend on the precise pathway of Gag mRNA export from the nucleus, known to be mediated by Rev. Here we describe an assembly deficiency in human cells for HIV Gag whose expression depends on hepatitis B virus (HBV) post-transcriptional regulatory element (PRE) mediated-mRNA nuclear export. PRE-dependent HIV Gag expressed well in human cells, but assembled with slower kinetics, accumulated intracellularly, and failed to associate with a lipid raft compartment where the wild-type Rev-dependent HIV-1 Gag efficiently assembles. Surprisingly, assembly and budding of PRE-dependent HIV Gag in human cells could be rescued in trans by co-expression of Rev-dependent Gag that provides correct membrane targeting signals, or in cis by replacing HIV matrix (MA) with other membrane targeting domains. Taken together, our results demonstrate deficient membrane targeting of PRE-dependent HIV-1 Gag and suggest that HIV MA function is regulated by the trafficking pathway of the encoding mRNA

Land Use PLanning Models: An Experiment in Interdisciplinary Education

This paper describes an experiment in interdisciplinary education that focuses on quantitative 1 and use planning techniques. Lectures introduce students to a variety of planning models.. Through coordinated individual and team research, students develop alternative models that are applied to a relevant, local, real world, land use planning problem

A Method for Merging the Results of Normative and Positive Models

Excerpt from the Introduction: For many years economists have been discussing the differences between normative and positive models and debating the advantages and disadvantages of these two alternative approaches. This research note does not either review the literature or settle, once and for all, the question of which methodology is the "best". It merely proposes and illustrates a simple rule of thumb that appears to give reasonable answers for agricultural economists who earn a living by doing impact analyses with policy models. This rule of thumb is designed for use in a "with and without" analysis study

A Method for Maximizing the Present Value of a Groundwater Resource

From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, ArizonaIn the past, researchers have applied a variety of analytical techniques for maximizing the present value of net benefits derived from a stock resource-simulation, calculus of variations, stochastic dynamic programming, and optimal control theory. This paper presents a more operational approach - linear programming. Applying linear programming to this type of problem requires a set of internal accounting constraints that prevent the additivity assumption of linear programming from being violated. A simplified, broadly drawn example from Southwest agriculture is used for demonstrating the model's structure and output.This article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]

The Stochastic Effects of a Ban on Toxaphene Use on Cotton

A ban on toxaphene use In control of the cotton budworm bollworm would Increase the average price of cotton 8S well as Its Price instability It would decrease the level and Increase the variability of cotton Yield and production Such 8 ban would also decrease the expected value but not the veflonC8 of exports A Monte Carlo economic simulation model was used to evaluate stochastic Impacts of pesticide regulation This methodology should be applicable also In future technology Impact policy analyse

A MODEL 0F VOTING BEHAVIOR FOR REVEALING PUBLIC SECTOR DEMANDS

Two major political problems that face every community are: (1) to determine how much money the local government should spend and, given that quantity as a budgetary constraint; (2) what percentage of the budget should be allocated to each category of publicly provided goods and services. A new type of survey instrument, the bidding game, can be used to address the second problem. Commnunity attitudes are revealed by allowing each respondent to spend play money to construct his, or her, preferred budget. The outcomes of these games are utilized to construct a median budget. A mathematical model of political equilibrium suggests that a median budget will win a two way election with any other budget. Preliminary, quasi-experimental results support· this hypothesis